The present invention relates generally to hoists for lifting loads. More specifically, the present invention consists of a lightweight, portable boom and prop that can be used in association with virtually any ladder to lift loads. This apparatus is especially suitable for use in lifting loads on to the roof of a building in the construction, roofing, or air conditioning trades.
The prior art contains several references showing various types of pulley arrangements fastened or attached to a ladder to raise or lower loads, e.g., U.S. Pat. Nos. 3,743,227; 2,803,389; 2,628,071; 2,459,621; 2,319,893; 799,782; and 731,708. The prior art also discloses various brackets, props, or supports to secure and hold a ladder away from the wall or roof of a building, e.g., U.S. Pat. Nos. 4,331,217; 4,164,269; 2,432,189; 2,407,541; and 543,513. The primary differences between the prior art and the present invention involve the specific structure of the boom and prop that allows the apparatus to be more compact, lightweight, portable, and adaptable to a variety of ladders that the prior art references. With the present invention, the boom assembly and prop can each be easily carried up the ladder, put in place, and used by a single person. In contrast, the apparatus disclosed in U.S. Pat. No. 2,803,389, has both a variety of boom and a support to hold the ladder away from the building. However, this apparatus is far more bulky and cumbersome to carry up the ladder and to use.